This invention relates to articles sensitive to non-ionizing electromagnetic radiation in the radiofrequency range.
Exposure to microwave power can lead to pathophysiologic effects. In laboratory animals, the microwaves penetrate beneath the skin and heat the tissue. Tissue destruction can result if the temperature rise is faster than the control mechanisms of the body can handle. In the United States, the maximum recommended exposure for humans is 10 mW/cm.sup.2 for durations greater than 6 minutes.
Devices designed for detecting and recording exposure to non-ionizing electromagnetic fields are electronic devices that measure magnetic fields, electric fields, or the heat resulting from absorption of such radiation into dielectric materials. The most common detector is a silicon diode designed for high frequencies and mounted in a waveguide or stripline. The diode rectifies the signal and produces an average current that can be indicated by a direct-current meter. Another common detector absorbs microwave power, causing a temperature change and a corresponding change in resistance. Devices for the detection of temperature changes with absorption of radiofrequency (rf) radiation may be photonic rather than electronic, depending on real-time decreases in fluorescence of inorganic crystalline material when heated, together with fiberoptics to transfer the light to an electronic recording device. What is desired is a non-electronic device for detecting and recording exposure to non-ionizing electromagnetic fields.
Accordingly, it is an object of the present invention to provide a non-electronic device for detecting and recording exposure to non-ionizing electromagnetic fields.
It is another object of the invention to provide a method for preparing such a device. Other objects, aspects and advantages of the present invention will be apparent to those skilled in the art from a reading of the following detailed disclosure of the invention.